Using digital broadcasting, digital high-vision broadcasting, content delivery over a broadband network or NGN (Next Generation Network), or IPTV (Internet Protocol Television), an end user receives content, including video and audio, at home and accumulates the received content in a hard disk recorder or the like in the home.
In addition, an end user accumulates still image content and moving image content taken by the end user himself or herself using a digital camera or a digital video camera. A service is being studied or is supplied on a trial basis to allow not only the end user himself or herself but also limited viewers to view those various types of video content at home and outside the home. For example, a method is proposed to allow a user to view content, which is accumulated in an in-home apparatus compatible with DLNA (Digital Living Network Alliance) described in IEEE CCNC 2008 “Proposal on Wide are DLNA Communication System”, pp. 233-237, 2008, directly on a mobile phone outside the home, or to allow specified users to share the content, via a home gateway.
For example, Patent Document 1 (Japanese Patent Kokai Publication No. JP2002-77274A) discloses a home gateway that has the configuration described below to provide a communication system that can protect against an attack from a malicious user of a home network without requiring the home gateway (an in-home gateway) to have an excessively high security function or without requiring the user to perform management usually performed by a specialist. In this configuration, in order to access a communication apparatus on a home network via the Internet, a mobile terminal transmits a message to an access server by specifying an access number corresponding to the home gateway. The access server performs an authentication procedure with the mobile terminal using a method predetermined for the mobile terminal and, when the authentication is successful, transfers a message, via the access network, to the home gateway which corresponds to the specified access number and is installed on the home network. The home gateway, which receives the message from the pre-registered access server, transfers the message to a communication apparatus via the home network. In Patent Document 1, the mobile terminal transmits a message to an access server by specifying the access number corresponding to the home gateway and, when the authentication with the access server is successful, the access server transfers the message to the home gateway corresponding to the access number and installed on the home network. The home gateway converts the message to a protocol supported by a communication apparatus connected to the home network, and transfers the converted message to the communication apparatus. The home gateway performs preset conversion processing for AV data of a predetermined-format received from the communication apparatus and relays the converted AV data to the access server. The preset conversion processing described in this document is code conversion processing for converting the AV data for processing on the access network.
The configuration in which a mobile terminal accesses an in-home apparatus via a home gateway is disclosed, for example, in Patent Document 2 (Japanese Patent Kokai Publication No. JP2006-352286A). In this configuration, when a mobile phone is used to control electrical home appliances (for example, TV, DVD/HDD recorder, air conditioner, lighting fixtures, etc.,) or housing-facility equipments (for example, electrical door lock, several types of sensors, etc.,) connected to a home gateway, the following method is used to provide a highly-secure access technology for preventing an unauthorized access to the home network while reducing the load of the access server that performs authentication. The connection management apparatus authenticates the mobile phone and, when an access from the mobile terminal is permitted, the home gateway communicates, not via the connection management apparatus, but directly with the mobile phone (peer-to-peer communication) to allow the mobile phone to control the in-home apparatuses. In addition, to prevent an unauthorized access, the configuration is disclosed in which the authentication is performed again (second authentication) when the peer-to-peer communication is started. Patent Document 2 describes that the configuration makes it possible to carry out highly secure communication with a home network while reducing the load of the access management server (connection management apparatus), that the configuration can be used for the large-capacity data communication service, for example, the content accumulated in an in-home DVD/HDD recorder can be downloaded to an out-of-home apparatus by controlling the recorder from an out-of-home location, and that the configuration is suitable for preventing an unauthorized access and increasing the security to implement the services.
Patent Document 3 (Japanese Patent Kokai Publication No. JP2007-312148A) discloses a home gateway apparatus that reduces a load of a server, and ensures high security to implement communication adapted to a number of model types of out-of-home apparatuses. The home gateway apparatus, connected to an out-of-home apparatus and an external gateway apparatus via a network, is configured to include a storage unit that stores information on a predetermined apparatus and an access control unit that controls access to the out-of-home apparatus. The access control unit transmits the information on the predetermined apparatus, acquired from the storage unit, to the external gateway apparatus. When the external gateway apparatus determines that the information on the out-of-home apparatus acquired from the out-of-home apparatus corresponds to the information on the predetermined apparatus, the access control unit controls to communicate with the out-of-home apparatus not via the external gateway apparatus.
Patent Document 4 (Japanese Patent Kokai Publication No. JP2008-283648A) discloses an in-home apparatus control system. In this in-home apparatus control system, a femto base station that has a small service area in the home is provided and an in-home apparatus control server stores a registered terminal database that stores information on a terminal ID and the state of each terminal indicating whether the terminal is in or out of the area and a control apparatus database that specifies correspondence between the operation of an in-home apparatus and each terminal location state used as a trigger of the operation. The femto base station transmits the ID of a terminal 1 entering and exiting the area and the entering/exiting information to the server, the server updates the status of the registered terminal database based on the received information and, if the updated state matches a trigger stored in the control apparatus database, controls the in-home apparatus so that the in-home apparatus performs an operation which becomes the same as that stored as an operation corresponding to the trigger.
Patent Document 1:
    Japanese Patent Kokai Publication No. JP2002-077274APatent Document 2:    Japanese Patent Kokai Publication No. JP2006-352286APatent Document 3:    Japanese Patent Kokai Publication No. JP2007-312148APatent Document 4:    Japanese Patent Kokai Publication No. JP2008-283648A